Solenoid valve

Abstract

In a solenoid valve, a gap is formed between a solenoid, which includes a stator housed within a resin mold, and a retainer that secures the solenoid on a housing. The gap communicates with a armature chamber that houses the armature mounted on a front end of a plug valve. High-pressure fuel is charged from the fluid passage into the armature chamber and flows into the gap around the solenoid to apply even pressure to the periphery of the resin mold as well as to the intake end surface of the solenoid. This prevents deformation of the resin mold and, consequently, distortion of the intake end surface. Such distortion can also be prevented by internally fitting a protective plate made of a non magnetic body in the opening ends of the coil grooves formed in the intake end surface of the stator.

What is claimed is: 
     
       1. A solenoid valve comprising: a housing defining a through hole, a fluid passage communicating with said through hole, and a chamber in fluid communication with said through hole;   a plug valve slidably mounted in said through hole to control communication between said through hole and said fluid passage;   an armature positioned in said chamber and connected to said plug valve;   a solenoid including a synthetic resin mold and a stator positioned in said synthetic resin mold, said solenoid located so as to oppose a surface of said armature;   a spring operatively engaging said plug valve to bias said armature in a direction away from said stator; and   a retainer enclosing said synthetic resin mold and mounting said solenoid to said housing, wherein said retainer is spaced from said synthetic resin mold so as to form a gap therebetween and said chamber is in fluid communication with said gap.   
     
     
       2. The solenoid valve as claimed in claim 1, wherein said stator is formed of a plurality of thin plates and includes an open-ended groove formed therein, said solenoid further comprising: a plurality of coils provided in said grooves; and   a non-magnetic metal core plate connected to said stator so as to align an end surface of said stator with an end surface of said core plate.   
     
     
       3. The solenoid valve as claimed in claim 2, further comprising a synthetic resin seal provided at the open end of said groove. 
     
     
       4. The solenoid valve as claimed in claim 2, wherein said retainer is cylindrical and includes an open end, a closed end, a pair of holes therethrough and a stepped portion formed on an interior peripheral wall of said retainer, said solenoid further comprising: a pair of terminals extending through said holes;   an air-tight seal provided between each terminal and said respective retainer hole.   
     
     
       5. The solenoid valve as claimed in claim 2, wherein said retainer is threadedly connected to an outer wall portion of said housing, a first peripheral surface of said core plate engages an end of said housing, and a second peripheral surface of said core plate engages said retainer so that said core plate is clamped between said housing and said retainer. 
     
     
       6. The solenoid valve as claimed in claim 2, further comprising a communicating passage formed in said core plate to provide communication and pressure equalization between said chamber and said gap. 
     
     
       7. The solenoid valve as claimed in claim 1, wherein said solenoid further comprises a plurality of coaxial terminals which extend through a central axial hole in said retainer. 
     
     
       8. The solenoid valve as claimed in claim 1, further comprising: a tapered portion formed on said plug valve; and   a valve seat formed on an inner peripheral wall of said housing through hole, wherein said tapered portion is engagable with said valve seat to prevent communication between said fluid passage and said chamber.   
     
     
       9. The solenoid valve as claimed in claim 1, wherein said fluid passage and said chamber are in fluid communication when said solenoid is not actuated, and said plug valve cuts off fluid communication between fluid passage and said chamber when said solenoid is actuated. 
     
     
       10. A solenoid valve comprising: a housing defining a through hole, a fluid passage communicating with said through hole, and a chamber in fluid communication with said through hole;   a plug valve slidably mounted in said through hole to control communication between said through hole and said fluid passage;   an armature positioned in said chamber and connected to said plug valve;   a solenoid including a synthetic resin mold, a stator positioned in said synthetic resin mold, and a coil groove formed in said stator, said coil groove having an open end in a surface of said stator opposing said armature;   a spring operatively engaging said plug valve to bias said armature in a direction away from said stator; and   a protective plate formed of non-magnetic material and positioned in said open end of said coil groove.   
     
     
       11. The solenoid valve as claimed in claim 10, wherein said open end of said coil groove is annular and said protective plate is formed in an annular shape defining a central open area which corresponds to said groove, and a central portion of said stator projects into said open central area of said protective plate. 
     
     
       12. The solenoid valve as claimed in claim 11, wherein said portion of said protective plate, which extends into said coil groove, includes an inner wall projecting from an interior edge of said plate and engaging an inner peripheral wall of said coil groove, and an outer wall projecting from an exterior edge of said plate and engaging an outer peripheral wall of said coil groove. 
     
     
       13. The solenoid valve as claimed in claim 10, further comprising an annular non-magnetic core plate connected to said stator so as to align an end surface of said stator with an end surface of said core plate, wherein said stator is comprised of a plurality of laminated thin plates and said coils are wound within said coil groove. 
     
     
       14. The solenoid valve as claimed in claim 13, further comprising a stepped portion formed on an inner peripheral surface of said core plate, wherein said protective plate engages said stepped portion to maintain a specific position relative to said armature. 
     
     
       15. The solenoid valve as claimed in claim 12, further comprising a synthetic resin provided on a portion of said protective plate in such a manner that other portions of said protective plate are not provided with a synthetic resin. 
     
     
       16. The solenoid valve as claimed in claim 10, further comprising a retainer threadedly connected to an outer wall portion of said housing, wherein a first peripheral surface of said core plate engages an end of said housing and a second peripheral surface of said core plate engages said retainer so that said core plate is clamped between said housing and said retainer. 
     
     
       17. The solenoid valve as claimed in claim 10, further comprising: a tapered portion formed on said plug valve; and   a valve seat formed on an inner peripheral wall of said housing through hole, wherein said tapered portion is engagable with said valve seat to prevent communication between said fluid passage and said chamber.   
     
     
       18. The solenoid valve as claimed in claim 10, wherein said fluid passage and said chamber are in fluid communication when said solenoid is not actuated, and said plug valve cuts off fluid communication between fluid said passage and said chamber when said solenoid is actuated.